Social games according to related arts include a known video game wherein players battle with each other by using a concept of “deck” (“Sengoku Royale,” [online], Apr. 20, 2010, DeNA Co., Ltd., [Searched on May 29, 2012], the Internet, <URL:http://sngk.mbga.jp/_sngk_top>). A deck is a game content group constituted by a plurality of game contents (such as character cards) selected from game contents owned by a player, and the game content group is used by the player. The strength of a deck is determined based on, for example, characteristic values (e.g., offensive power and defensive power) assigned to each game content constituting the deck and combination of game contents constituting the deck (e.g., special abilities produced by affinity and combination). Additionally, teams each including a plurality of players can battle with each other (team battle).